Limitation of heavy metal dispersion out of polluted sites by means of phytostabilization strategy : a laboratory study
(2013)
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- Abstract
- (en) Phytostabilization is a management strategy aiming at limiting risks of heavy metal dispersion out of a polluted area by means of the use of appropriate plant species and soil amendments. Several aspects of this technique were studied based on laboratory experiments. We first clarified heavy metal mobility and bioavailability terms and showed what different laboratory measurements performed on contaminated soil samples can really indicate about these concepts. An interesting output of this work was the demonstration that heavy metal mobility and plant uptake are not always positively correlated. The impact of 2 contrasted soil amendments on heavy metal mobility, uptake by perennial ryegrass and metal leaching was assessed based on specifically-designed pot experiments. The suitability of steel shots for phytostabilization purposes was shown, but also that the development of plant species into a polluted soil could sometimes lead to an increased risk in metal leaching. Column experiments performed with ryegrass and white clover and with Cd- and Zn-contaminated substrates highlighted a potential risk linked to metal phytostabilization, i.e., a metal-induced impairment of root distribution within the soil profile which could decrease the longevity of the plant cover and limit soil stabilization. The use of an experimental flume allowed us to investigate the mechanisms of metal trapping by vegetative filter strips (VFS) during water erosion events. The effectiveness of a plant species to control soil erosion varied according to its growth and development dynamics. We showed also that the retention of metal contaminants by VFS was affected not only by the sediment retention, but also by the metal concentration in the various particle size classes. This metal distribution between the different particle size fractions varied according to the pollutant and soil physico-chemical properties as well as the nature of the pollution. Lessons from these experiments were combined with feedbacks from field trials in the literature to propose some guidelines for the in situ implementation of phytostabilization strategies. Such field experiments are decisive for the future of phytostabilization.
- Affiliations
UCLouvain SST/ELI/ELI - Earth and Life Institute
Citations
Lambrechts, T. (2013). Limitation of heavy metal dispersion out of polluted sites by means of phytostabilization strategy : a laboratory study. https://hdl.handle.net/2078.5/204415